1. Field of the Invention
The present invention relates generally to class of line identifiers and more particularly to coin or pay telephone line identifying circuits.
2. Description of the Prior Art
The purpose of the following invention is to provide a positive means for identifying a coin or a pay telephone wherever it is located, in whatever number group, throughout the telephone system.
Traditionally, coin or pay telephones have been assigned telephone numbers in the 9000 series connector number group with an appropriate prefix and area code. The operator handling a collect telephone call to such an assigned pay telephone number realizes, by the above group assignment, that such a telephone is a pay telephone and that collect calls cannot be connected to it.
Unfortunately, in smaller telephone exchanges and in larger metropolitan areas, with multiple telephone exchanges, many coin or pay telephones are assigned to numbers outside the traditional 9000 series connectors. In large metropolitan areas, increased coin telephone installations have, in some cases, used up the traditionally assigned pay-station number category. In small rural areas, such calling groups simply may not be available. In either case, an operator, (TSPS) or other, at the calling location cannot tell if the number called, which may be 2000 miles away, is a coin telephone. Indeed, in some areas, lack of sufficient central office connector lines has caused business or residential telephones to actually be assigned a number in the 9000 number group traditionally reserved for coin numbers.
Whatever the reason for the unidentified assignment, collect calls are being made to pay telephones by users having fraudulant intent. This results in a subsequent loss of revenue to the telephone company; this loss must be passed on to the general rate-paying subscribers. There is currently no available electronic circuit for positively identifying a called pay telephone line that may have a number assignment which is outside the traditional number group.
The problem is simple. In the case of a collect call to a pay telephone not in the traditional number group, the charges are uncollectable unless the operator is made aware that the called number serves a line connected to a pay telephone. Currently, the operator is not able to know whether the called telephone is a pay telephone and, thus, numerous collect long distance calls are made without being properly billed. This is especially true when a collect long distance call is made from one pay telephone to another by persons, agreeing in advance, to call at a specific time.
Another more recent problem relates to telephones in school dormitories or similar locations where no single party is responsible for long distance toll charges. Present procedures can control out-going calls and route them through an operator, but there is essentially no control on in-coming collect calls.
The inventors are aware of the following prior art:
______________________________________ Inventor Pat. No. Date ______________________________________ Conway 1,700,469 Jan. 29, 1929 Collis et al 2,299,212 Oct. 20, 1942 Wicks 2,544,944 Mar. 13, 1951 Grimes 2,546,067 Mar. 30, 1951 West et al 2,557,487 June 19, 1951 Balzer et al 2,569,650 Oct. 2, 1951 Smith 3,169,170 Feb. 9, 1965 Blashfield 3,201,523 Aug. 17, 1965 Johansen et al 3,534,174 Oct. 13, 1970 Knox 3,553,382 Jan. 5, 1971 Regniere 3,651,275 Mar. 21, 1972 Lee, Jr. et al 3,671,677 June 20, 1972 Mogtader 3.920,936 Nov. 18, 1975 ______________________________________
None of the above prior art patents suggest or disclose an approach for identifying a called telephone line. The 1951 patent to West teaches the use of a separate reply signal circuit for providing a signal from the receiving or called end to the sending or calling end in the event that the called telephone does not answer. The patents to Mogtader, Lee, Jr. et al., Regniere, Blashfield, and Wicks teach the use of various circuit configurations by which calls to unauthorized called numbers are detected and diverted to an operator for an intercept or for denying service thereto. In all cases, the detection of the unauthorized called number is detected at a location near the calling number.